1. Field of the Invention
The present invention relates generally to an apparatus and a method for forming a pattern, and in particular, to an apparatus and a method for forming a pattern for the formation of quantum dots or wires with 1˜50 nm dimension using the atomic array of a crystalline material and to the manufacture of functional devices that have such a structure.
In the present invention, the functional device means an electronic, magnetic, or optical device that can be fabricated by procedures including the formation process of quantum dots or wires.
2. Description of the Related Art
The formation process of quantum dots or wires becomes the core process for the fabrication of an electronic, magnetic or optical device with quantum dots or wires as the application of such devices is increasingly expected. A fundamental operating principle of such devices is based on quantum mechanical results that the physical properties of the particle are greatly affected by its size as it becomes nanometer-sized. Particularly, there are many researches for the single electron transistor which has been suggested as the alternative to MOS device in order to overcome the limitation of the MOS device that has been developed continuously for 40 years.
Previous researches on the formation processes of quantum dots or wires can largely be divided as follows.
First, there is a method in which one or a few quantum dots or wires are formed by AFM (Atomic Force Microscopy), STM (Scanning Tunneling Microscopy) and electron beam lithography. This method has the capability to form the quantum dots or wires whose size and location are controlled experimentally, but has difficulty in applying to mass production because of a low throughput.
Second, there is a method in which quantum dots or wires are formed by the process of patterning and etching. In this method, patterning means the formation process of quantum dots or wires on the substrate by the electron beam direct-writing, or by the etching of the chemical substance which was imprinted by the mask or mold made with an electron beam.
Third, there is a method in which quantum dots or wires are formed by the nucleation at the early state of phase transition of materials. This method has can be applied to mass production, but has problems in controlling the size, density or distribution of quantum dots or wires.